a. Field of the Invention
The present invention relates generally to insoles for footwear, and, more particularly, to a contoured insole having a soft cushioning upper blank and a rigid reinforcement cap which extends around the heel end of the blank so as to provide support at predetermined areas of the insole.
b. Background Art
Cushioning insoles of various types are known for use in shoes, particularly for use in running shoes and other shoes intended for athletic activities. Typically, these insoles take the form of a relatively thin layer of foam material which rests atop the sole of the shoe, and are often removable for washing or replacement.
While commonly used, conventional insoles of this general type have proven less than ideal in several respects. Firstly, the top surface of the foam material is often given a pronounced contour in an effort to support and cradle the wearer's foot, but because the foam is intended mainly to cushion the foot, it typically lacks sufficient strength and firmness to simultaneously provide the necessary support for proper biomechanical function of the foot, particularly in the rearfoot and arch areas. This problem is aggravated by the fact that most athletic shoes are "soft sided" to a greater or lesser extent, i.e., the uppers are formed of cloth, vinyl, or other flexible materials which yield outwardly under pressure, thereby providing very little inward buttressing around the insole. As a result, conventional contoured insoles tend to deform and "mush" downwardly and outwardly under the foot without providing any meaningful level of support, and also tend to break down and lose their shape very rapidly in use.
Some efforts have been made to correct these problems by including higher durometer materials in one or more areas of the device. For example some cushioning insoles have been constructed with a band of heavier durometer rubber or similar material added in the arch area and around the heel of the foam footbed. However, these materials has done little if anything to increase the strength or durability of the insoles, and they have not had the strength or configuration necessary to provide proper support for the wearer's foot.
One form of device which does offer a high degree of durability and support is that which is disclosed in U.S. Pat. No. 4,597,196. This device includes a full-length resilient blank formed of rubber or similar material, with a resilient pad extending longitudinally down the bottom of the blank and a somewhat horseshoe-shaped moldable cork member extending along the sides and around the heel area. The assembly also includes a fairly rigid plastic cap which fits over the bottom of the device and extends partway up the rearfoot sides. However, while highly successful for its intended purposes, this device is principally a custom-molded, multi-component unit, and is consequently comparatively expensive and specialized in nature. Moreover, it is a fairly heavy device, and the added weight may not be desirable in many circumstances, particularly for use in certain athletic shoes.
In short, the construction which is shown in the '196 patent provides a somewhat "high end", specialized product, which is not particularly well suited to the low cost, high volume athletic shoe market.
Accordingly, there exists a need for a lightweight, low-cost contoured insole which provides effective cushioning for a foot, yet which is nevertheless durable and longlasting in use. Furthermore, there exists a need for such an insole which provides proper support in the heel and rearfoot areas so as to optimize the biomechanical motions of the foot.